WOMS
P code powertrain High severity

P1813 Transmission 4-Wheel Drive Mode Select Open Circuit

The OBD2 code P1813 indicates that there is an open circuit in the transmission's 4-wheel drive mode select system, which can affect the operation of the 4WD system

Definition

The OBD2 code P1813 indicates that there is an open circuit in the transmission's 4-wheel drive mode select system, which can affect the operation of the 4WD system

Common causes

  • Faulty mode select switch
  • Open or shorted wiring
  • Poor electrical connections
  • Failed transfer case control module
  • Damaged or corroded connectors
  • Faulty transmission control module
  • Blown fuse related to the 4WD system

Common misdiagnoses

  • Faulty transfer case switch
  • Wiring issues or shorts
  • Faulty transmission control module (TCM)
  • Defective 4WD actuator
  • Incorrectly diagnosed transmission problems
  • Faulty vehicle speed sensor
  • Issues with the transfer case itself
  • Problems with the main wiring harness
  • Low transmission fluid levels
  • Faulty or corroded connectors

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify related issues

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring and connectors associated with the 4WD mode select switch and the transmission control module (TCM)

  3. 3. Look for signs of damage, corrosion, or loose connections. Pay special attention to any frayed wires or broken connectors

  4. 4. Test the 4WD Mode Select Switch

    Use a multimeter to test the functionality of the 4WD mode select switch. Ensure that it is operating correctly and sending the appropriate signals to the TCM

  5. 5. If the switch is faulty, it may need to be replaced

  6. 6. Check the Transmission Control Module (TCM)

    Inspect the TCM for any signs of damage or corrosion. Ensure that it is securely connected and that there are no issues with the pins or connectors

  7. 7. If necessary, test the TCM to ensure it is functioning properly. This may require specialized diagnostic equipment

  8. 8. Inspect the Transfer Case

    Check the transfer case for any mechanical issues that could affect the 4WD operation. Ensure that it is properly engaged and that there are no internal faults

  9. 9. Look for any leaks or damage that could impact the operation of the transfer case

  10. 10. Check for Ground Issues

    Ensure that all ground connections related to the transmission and 4WD system are secure and free of corrosion. Poor grounding can lead to electrical issues

  11. 11. Perform a Visual Inspection of the Transmission

    Inspect the transmission for any signs of damage or wear that could affect its operation. Look for fluid leaks or other issues that may need to be addressed

  12. 12. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner

  13. 13. Take the vehicle for a test drive to see if the code reappears. Monitor the 4WD operation to ensure it is functioning correctly

  14. 14. Consult a Professional

    If the issue persists after performing these troubleshooting steps, it may be necessary to consult a professional mechanic or technician who has experience with transmission and 4WD systems. By following these steps, you should be able to identify and resolve the issue related to the P1813 code. Always refer to the vehicle's service manual for specific diagnostic procedures and specifications